The present invention relates to the processing of pourable materials.
More particularly, the invention relates to the processing of particulate pourable materials, such as sand and other particulates.
Still more specifically, the invention is directed to a method of effecting such processing and to apparatus for carrying out the method.
There are various applications in which particulate materials are received in moist condition and must be dried prior to further processing. One example of such an application is in the foundry art, where moist sand for casting purposes must be dried before it can be used. Another example is the manufacture of dry mortar mix.
In all these instances the drying is carried out with the aid of heat energy. The more of this energy there is lost, the more expensive will be the overall operation. Recovery of the thermal energy is, however, rather difficult and can itself be carried out only at rather substantial expense. For example, heat may be recovered by heat exchange between the dried and heated pourable material and water which circulates through cooling pipes which have contact with the material. Another possibility is to pass cool air through the hot material and to recover some of the thermal energy by heat exchange of the air with the material. It is also known to moisten the dried and still hot material, so that the latent heat of evaporation constitutes a means of heat-energy recovery. However, in all these cases the recovery is on a very minor scale, which is to say that the amount of heat lost is very substantial.